GE Multilin 745 Transformer Management Relay 745-W2-P5-G5-HI-A-L-R-E-H Original new

The GE 745‑W2‑P5‑G5‑HI‑A‑L‑R‑E‑H is a microprocessor‑based digital relay engineered by GE Multilin to deliver primary and backup protection, monitoring, and control for medium to large power transformers. Part of the SR product family, the GE 745‑W2‑P5‑G5‑HI‑A‑L‑R‑E‑H integrates variable dual‑slope differential protection (87T) with second‑ and fifth‑harmonic restraint to distinguish energization inrush from internal faults. The GE 745‑W2‑P5‑G5‑HI‑A‑L‑R‑E‑H offers comprehensive I/O, multiple communications ports, an enhanced LCD, and powerful automation via FlexLogic™ programmable logic. The drawout case, conformal coating, and wide‑range control power make the GE 745‑W2‑P5‑G5‑HI‑A‑L‑R‑E‑H suitable for harsh utility and industrial environments, reducing downtime and extending transformer life.

• Primary protection – Power transformers (two‑ or three‑winding), generator step‑up (GSU) units

• Backup protection – For transformers, reactors, and adjacent transmission lines

• Substation automation – Stand‑alone or integrated into bay‑level control systems

• Industrial power – Chemical plants, refineries, steel mills, and data centers

• Renewable energy – Transformers in solar, wind, and hydro power plants

• Asset management – Hottest‑spot temperature, aging factor, and loss‑of‑life monitoring

• Overload monitoring – For large motor or generator transformers

• Critical grid infrastructure – Where high reliability and rapid fault clearance are required

• Variable dual‑slope percentage differential – Adjustable slope‑1 (15‑100%) and slope‑2 (50‑100%) with independent kneepoint for better sensitivity and through‑fault stability.

• Adaptive 2nd harmonic restraint – Programmable restraint methods (2nd, 2nd+5th, energization‑based) to prevent maloperation during magnetizing inrush.

• Fifth harmonic inhibit – Dedicated element to block differential tripping during V/Hz overexcitation.

• Unrestrained instantaneous differential – Fast tripping on heavy internal faults to limit equipment damage.

• Restricted ground fault (RGF) – Zero‑sequence differential for sensitive detection of low‑magnitude ground faults in star‑connected windings.

• Complete overcurrent suite – Phase, neutral (3I₀), ground, and negative‑sequence elements with multiple curve shapes (IEEE, IEC, GE IAC, FlexCurves™) and definite time.

• Frequency protection – Underfrequency (2 elements), overfrequency (1 element), and rate‑of‑change (4 elements) for load shedding and generator runback.

• Overexcitation (V/Hz) protection – With definite time or IEC curves to prevent core damage.

• Transformer asset monitoring – Calculates hottest‑spot temperature, aging factor, and loss‑of‑life (IEEE Std C57.91‑1995 / C57.96‑1989).

• Auto CT configuration – Automatic phase and magnitude correction plus zero‑sequence compensation for over 100 transformer types.

• Dynamic CT ratio mismatch correction – Monitors on‑load tap changer (OLTC) variations.

• Multiple setting groups – 4 independent groups selectable via logic inputs, front panel, or communications.

• FlexLogic™ programmable logic – Custom protection and control schemes without external components (interlocking, dynamic setting group changes, etc.).

• Drawout case – Fully removable unit with automatic CT shorting; minimizes maintenance downtime.

• Conformal coating – Optional thin polymer layer (−H suffix) for harsh/chemical/humid environments.

• Wide‑range control power – Accepts 90‑300 V DC or 70‑265 V AC, simplifying retrofit and eliminating external converters.

• Field‑upgradeable firmware – Pass‑code key option for adding features in the field.

• Simulation mode – Test relay logic and settings by injecting arbitrary waveform data.

• High‑resolution event recording – 256 time‑tagged events with 1 ms accuracy.

• Oscillography and data logger – Capture up to 32 power cycles of analog/digital data with COMTRADE export.

• Harmonic analysis – Measures individual harmonics up to the 21st, THD, and Harmonic Derating Factor (ANSI/IEEE C57.110‑1986).

• Security audit trail – Tracks all configuration changes for regulatory compliance.

• IRIG‑B time synchronization – GPS‑synchronized timestamping for events and oscillography.

• Multiple communication ports – Front RS232 for local access; rear RS485/RS422; optional 10BaseT Ethernet (Modbus TCP/IP).

• EnerVista™ software suite – Setup, monitoring, archival, and integrator toolkit (OPC/DDE, automatic event/waveform retrieval).

• Detects internal transformer faults – Compares differential current against dual‑slope bias with harmonic restraint, issuing trip commands while ignoring inrush and overexcitation.

• Clears high‑magnitude faults quickly – Unrestrained differential element trips without intentional delay for severe internal events.

• Provides backup protection – Phase, neutral, ground, and negative‑sequence overcurrent elements (IOC/TOC) with selectable curve shapes.

• Prevents core overheating – V/Hz overexcitation element with definite‑time or inverse curves.

• Supports load shedding – Underfrequency and frequency rate‑of‑change elements for islanding or overload conditions.

• Monitors transformer health – Calculates hottest‑spot temperature, aging factor, and remaining insulation life based on IEEE standards.

• Executes custom logic – FlexLogic™ engine performs local interlocking, dynamic setting group switching, and permissive tripping without external relays.

• Records faults for analysis – Captures 256 events, 10 oscillography records, and data logs with 1 ms timestamp (IRIG‑B).

• Communicates with SCADA/DCS – Real‑time data exchange via Modbus RTU, DNP 3.0, or optional Modbus TCP/IP.

• Enables offline testing – Simulation mode allows waveform playback and relay verification without live power.

Q1: What does the suffix ‑H signify on the 745‑W2‑P5‑G5‑HI‑A‑L‑R‑E‑H?
A1: The ‑H suffix indicates that the 745‑W2‑P5‑G5‑HI‑A‑L‑R‑E‑H is equipped with a factory‑applied conformal coating. This thin polymeric layer protects the PCB from humidity, airborne contaminants, and mild chemical corrosion, making it suitable for harsh industrial environments.

Q2: What are the control power requirements for the 745‑W2‑P5‑G5‑HI‑A‑L‑R‑E‑H?
A2: The 745‑W2‑P5‑G5‑HI‑A‑L‑R‑E‑H accepts a wide‑range high‑level (HI) supply: 90‑300 V DC or 70‑265 V AC (48‑62 Hz). This allows direct connection to station batteries or AC control power without external converters.

Q3: Can the 745‑W2‑P5‑G5‑HI‑A‑L‑R‑E‑H be used on a two‑winding transformer as well as a three‑winding transformer?
A3: Yes. The 745‑W2‑P5‑G5‑HI‑A‑L‑R‑E‑H is designed for both two‑winding and three‑winding power transformers. Multiple current inputs enable differential and restricted ground fault protection for each winding.

Q4: Does the 745‑W2‑P5‑G5‑HI‑A‑L‑R‑E‑H require external interposing CTs to match winding configurations?
A4: No. The 745‑W2‑P5‑G5‑HI‑A‑L‑R‑E‑H features auto CT configuration – automatic phase and magnitude correction plus zero‑sequence compensation for over 100 transformer types. External interposing CTs are unnecessary.

Q5: Is the 745‑W2‑P5‑G5‑HI‑A‑L‑R‑E‑H still in production?
A5: The 745‑W2‑P5‑G5‑HI‑A‑L‑R‑E‑H is part of a legacy series. While it remains available through authorized channels and refurbished suppliers, users requiring current production should consult GE Grid Solutions (GE Vernova) for the latest recommended replacement.

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